Massive stars and their supernovae are prominent sources of radioactive
isotopes, the observations of which thus can help to improve our astrophysical
models of those. Our understanding of stellar evolution and the final explosive
endpoints such as supernovae or hypernovae or gamma-ray bursts relies on the
combination of magneto-hydrodynamics, energy generation due to nuclear
reactions accompanying composition changes, radiation transport, and
thermodynamic properties (such as the equation of state of stellar matter).
Nuclear energy production includes all nuclear reactions triggered during
stellar evolution and explosive end stages, also among unstable isotopes
produced on the way. Radiation transport covers atomic physics (e.g. opacities)
for photon transport, but also nuclear physics and neutrino nucleon/nucleus
interactions in late phases and core collapse. Here we want to focus on the
astrophysical aspects, i.e. a description of the evolution of massive stars and
their endpoints, with a special emphasis on the composition of their ejecta (in
form of stellar winds during the evolution or of explosive ejecta). Low and
intermediate mass stars end their evolution as a white dwarf with an unburned C
and O composition. Massive stars evolve beyond this point and experience all
stellar burning stages from H over He, C, Ne, O and Si-burning up to core
collapse and explosive endstages. In this chapter we discuss the
nucleosynthesis processes involved and the production of radioactive nuclei in
more detail.Comment: 79 pages; Chapter of "Astronomy with Radioactivities", a book in
Springer's 'lecture notes in physics series, Vol. 812, Eds. Roland Diehl,
Dieter H. Hartmann, and Nikos Prantzos, to appear in summer 201
